


Searching for a Mate

by thewinchesterlifestyle



Category: Supernatural
Genre: Bottom Castiel, Breeding, Come Inflation, Gender or Sex Swap, M/M, Merman Castiel, Mpreg, Octopus Alastair, Omega Castiel, Pregnant Castiel, Rough Sex, Tentacles, Tentacles Sex, clownfish merman castiel, top alastair
Language: English
Status: Completed
Published: 2016-02-13
Updated: 2016-02-13
Packaged: 2018-05-20 02:45:46
Rating: Not Rated
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 1,064
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/5989333
Author URL: https://archiveofourown.org/users/thewinchesterlifestyle/pseuds/thewinchesterlifestyle
Summary: <blockquote class="userstuff">
              <p>Castiel’s head fell back and his body quivered in pleasure at being bred. He had only recently changed to adapt his body for breeding. The number of females in his colony was significantly lower and he had adapted instead of competing with other males.</p>
            </blockquote>





	Searching for a Mate

**Author's Note:**

> Written for a prompt

Castiel slowly swam along the ocean floor as he headed back to his colony. He had hoped to find a mate, the only females in his colony firmly taken or already bred, and his body had adapted for the lack of females in hopes of increasing their numbers.

His eyes darted around and landed on a sunken ship. Curiosity had him swimming in that direction and peering into a jagged hole in the side of the hull. He blinked at the contents, crates mostly, as he leaned further in.

“Are you lost?” came a silky voice from behind him.

He yanked his head out of the hole, hissing when he cut himself and turned to regard a blood red colored octoman who had snuck up on him. Castiel furrowed his brow as he took in the thick tentacles and the evidence of battles.

The octoman had the build of a predator with strong tentacles and several scars Castiel was sure were from fights. He glanced at the sharp knife at the octoman’s hip and the cool eyes assessing him. “No.” Castiel didn’t elaborate even as he considered the octoman before him.

It wasn’t the most typical thing but there were several mates he’d come across both in his colony and Castiel _had_  adapted in order to reproduce himself. He watched how the octoman assessed him and he could see a potential mate.

Strength and skill were important if he wanted any of his offspring to succeed.

“I was looking to mate.”

There. He’d said it. Castiel swam away from the ship and towards the octoman. If the other made an attempt to attack he was confident he could swim faster and avoid falling prey to the octoman. “Oh?” now the cool look had turned to interest and Castiel could practically taste it in the water surrounding them.

Hands rubbed down his sides and ghosted over his slits as long tentacles slowly coiled around him, dragging him closer. Castiel could feel the strength in the hold even as he took in the pheromones of an aroused octoman. “Yes. A strong mate.”

A thick tentacle stroked against his slit, tested it and slowly started to sink in. Castiel’s lips parted on a choked gasp but his inner muscles easily yielded for the thick tentacle.

“I can’t  _breed_ you though…” the octoman frowned at the thought but it didn’t stop tentacles from completely encircling his tail and the rest of him. “Too bad. You feel good around me, little one.”

The tentacle pushed deeper inside and Castiel’s slit spread wide open around it as he shuddered. “Can be bred.” He managed and bit his lip to hold back a throaty moan.

Surprise flitted across the other’s face before something possessive and wild took over all emotion in the octoman’s eyes. “You can? I can breed you up?” the tentacle pushed in deeper and when Castiel glanced down he could see a bulge in his belly where it had pushed up into him. “You’re full of surprises.”

Castiel could only moan once the tentacle started to pump in and out of his slit, pushing all the way up into him until the tip pushed against his belly and moved back so suckers caught on his sensitive slit. His tail jerked and if the octoman hadn’t gotten a firm grip on him he would have sunk to the ocean floor.

“I’m going to fill you up, little one.” Castiel’s head fell back and his body quivered in pleasure at being bred. He had only recently changed to adapt his body for breeding. The number of females in his colony was significantly lower and he had adapted instead of competing with other males.

His slit rippled around the thick tentacle that pumped away inside him and spread him wide. There was a pleasant ache where he was full, every single nerve inside him alight with pleasure, as the octoman shoved deep and Castiel could  _feel_  warmth flooding him in thick, hot ropes.

“Ohhhh.” His eyes screwed up, his mouth dropped open in a silent cry, while the tentacles wrapped around him gripped him tightly and held him there.

The octoman kept him held close as he emptied his seed inside and Castiel gasped as suckers moved over him, holding tight and possessively. “It was lucky I chose to hunt by the wreck with a gorgeous little merman waiting to be bred up nearby.”

“Castiel.” He felt heavy and full as more and more of the octoman’s come poured into him as the tentacle continued to pulse inside him, shoved deep and plugging him up. “That’s my name not  _little one_ or _little merman_.”

The octoman arched a brow with amusement flashing across his face, “Castiel.” He drawled it out, lips quirking. “I prefer little one. You can call me Alastair. It will give you something to moan while I’m fucking you full.”

A flush heated Castiel’s face up as his tail swished in the water and his fingers curled. By now his belly was starting to bulge from the sheer amount of come being pumped inside him. It had him dizzy and surprised by the volume.

“I’ve always wanted to breed a merman. I didn’t realize so many of your kind could be bred.” He stroked Castiel’s face and grinned at him. It was a sharp, predatory look that had Castiel blinking and swallowing in shocked arousal.

“My kind can change if there is a lack of females.” He moaned lowly, “We were low on females…”

Alastair lazily pulled his tentacle back but Castiel could still  _feel_  Alastair’s release emptying inside him and when it thrust up into him he whimpered brokenly. “A pretty little gem. Who knew your kind could do something so useful?”

When Alastair finally finished, tentacle slowly retreating and suckers catching on his slit sending sparks of heat through him, his belly was swollen and Castiel felt very heavy. He panted and whimpered as Alastair kept him held in his tentacles.

His slit closed keeping every last drop of Alastair’s seed inside. “Useful. I can’t wait to see how full you are after another breeding.” Castiel shuddered at the thought of another thorough breeding. “Come on, little one. We’ve just started.” He found himself being hauled away, wrapped up in blood red tentacles, further away from his colony and into the darker reaches of the ocean.


End file.
